👻 EDR Evasion: Unhooking the Kernel

Abstract This article dissects the architectural flaws inherent in many modern Endpoint Detection and Response (EDR) solutions, specifically focusing on userland hooking mechanisms. We investigate sophisticated techniques, such as indirect syscall execution and API unhooking, employed by high-value threat actors to achieve persistence and functional invisibility. The goal is to move beyond generic bypass theory and provide deep technical analysis for security professionals building resilient defenses against advanced persistent threats (APTs). High-Retention Hook I remember spending three days chasing a simple dropper sample that kept vanishing. Not crashing, not terminating gracefully, but genuinely disappearing from memory right before execution, leaving zero forensic trace of its payload. I initially blamed my sandbox setup, convinced it was timing out. It wasn't. The sample was expertly checking for the tell-tale signs of userland security instrumentation: the injected DLLs, the mo